<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<style>
    .container {
        width: 50px;
        height: 50px;
        background: black;
        margin: auto;
        display: flex;
    }
    .container .item {
        width: 10px;
        height: 10px;
        background: red;
        border-radius: 50%;
        transform: rotate(45deg);
        transform-origin: center 40px;
    }
    .container .item2 {
        width: 10px;
        height: 10px;
        background: green;
        border-radius: 50%;
        /* transform: rotate(135deg);
        transform-origin: center 40px; */
    }
</style>

<body>
    
    <div class="container">
        <span class="item"></span>
        <span class="item2"></span>
    </div>

</body>
</html>